This invention relates generally to gas turbine engines and more particularly, to methods and apparatus for assembling gas turbine engines.
Known gas turbine engines include at least one rotor shaft supported by bearings which are in turn supported by annular frames. At least some known turbine frames include an annular casing that is spaced radially outwardly from an annular hub. A plurality of circumferentially-spaced apart struts extend between the annular casing and the hub. More specifically, within at least some known turbine engines, the struts, casing, and hub are integrally-formed together. In other known turbine engines, multi-piece frames are used in which only the struts and casing are integrally formed together.
Because at least some of the struts extend through a flow path defined within the engine, at least some of the struts are surrounded by, and extend through, a fairing that facilitates shielding the struts from hot combustion gases flowing through the flow path. More specifically, to facilitate increasing the structural integrity of fairings positioned in the flowpath, at least some known fairings are fabricated as a single-piece casting that includes at least one internal serpentine cooling passage. However, airflow and structural design requirements of such fairings may complicate the assembly of the struts to the engine frame. For example, because such fairings are unitary, the fairings may only be utilized with multi-piece frames. More specifically, each unitary strut is positioned around an inner end of each strut, slid radially outward towards a cantilevered end of each strut, and is coupled in position using a plurality of precisely-machined fastening/coupling hardware. Accordingly, because of the additional assembly and coupling hardware associated with multi-piece frames, and because of the tolerances that may be necessary to meet structural requirements, manufacturing and assembly costs of such frames may be more costly and time-consuming than associated with other known frames.